Discuz!_X2 笔记
单例模式(单一实例模式)
<?php
class db {
private static $obj = NULL;
private function __construct() {
}
private function __clone() {
}
public static function instance() {
if(!is_object(self::$obj)) {
self::$obj = new self();
}
return self::$obj;
}
}
?>....................